Printing machine pressure cylinder



July 20, 1943-, J. H. MAY 2,324,631-

I PRINTING MACHI NE PRESSURE CYLINDER Filed May is, 1941 I2 %sl63maentor I J HN )(n i w My G543 Patented July 20, 1943 UNITED STATESPATENT OFFICE 7 I 1 Claim. (Cl. 101-407) This invention relates toprinting apparatus and more particularly to the construction'of: the

' backing or pressure cylinder of a textile print against the ingmachine which holds the fabric pressure of the printing roll.

A standard type of textile printing machine comprises a'large freelyrotatable backing roll or cylinder having one or a plurality of printingrolls arranged to contact with the periphery thereof andforming aprinting couple between which the fabric is printed. The printing rollare driven by power mechanism and the backing cylinder is rotated'by thefrictional contact of the printing rolls against the fabric and theassociated back gray cloth and rubber blanket, if used, which passbetween the backing cylinder and the .rolls. The printing roll, mandrelis moved by means of pressure screws at its opposite ends which adjustthe: pressure applied to the fabric, and this pressure may vary from 1to 9Cor more tons at each end. The 'printingroll may be several feetlong, and the enormous pressure applied at each end thereof may causethe:

roll to bend slightly during the printing operation; so that if proper.provision were not made, the printing roll would press heavily againstthe fabric adjacent the ends of a'cylindrical nonelastic backing rolland would press lightly OIillOt at all at the middle portion of thefabric. Also, if the backing roll is small in diameter and mounted on alight mandrel, it too may be bent by theprinting pressure with the samegeneral results. l

It has, therefore; been customary to apply a thick layer of woolen orlinen padding or lapping on the backing roll or cylinder in such a way'as to form a slightly convex surface which fits the line of contact ofthe printing roll and insures proper engagement between the fabric to.be printed and the entire length of the engraved surface of theprinting roll. This cloth lapping must be laid on the cylinder by ahighly skilled expert, and each operator has his own ideas as to howthis should be done for a given type of printing and there is nouniformity of construction. Moreover, the lapping cloth must be used inlarge andcostly amounts and it wears out comparatively quickly, so thatthe machine is:

frequently out of commission for considerable periods as required forreplacing the lapping;

hence this type of construction has proven to;

be'inefficient and expensive.

It has been proposed to utilize a crownedwrub-v ber roll in place ofthat linen covered backing cylinder. That is, a cylindrical metal drumhas;-

been covered with a layer of rubber which has its middle portion thickerthan the edge portions so astoform a crowned convex surface. enormouspressure of the printing roll against 7 this central thickened portionof the rubber layer tends to cause the rubber to bunch up in ad- Vanceof the printing roll and to move laterally, and this may result in thefabric wandering irregularly and not tracking properly with the printingroll. Also, if astraight cylindrical iron cylinder were provided with alayer of rubber of row band of printing contact but, whatever may,

be the shape of the supporting roll, a layer of rubber which will bethus deformed will tend pattern if the surface of the cylinder roll issmooth. and does not, provide sufficient frictional engagement with thefabric. 1

The primary object of this invention is i to overcome such problems andto provide a textile printing apparatus in which the backing cylinder isso constructed and shaped that proper, pressure will be applied 3*tothe'fabric being printed throughout its entire width and the fabric willbe printed satisfactorily and prevented from wandering materially out ofregistry with the printing pattern. Further objects will 'be apparent inthe followingdisclosure. y it In accordance with my invention I havefound that a satisfactoryprinting. operation may be had if the backingor pressure cylinder ofthe printing couple is a composite body having acrowned convex surface carrying secured thereto a deformable elasticlayer of avulcanized rubber compound containing a reinforcing, flowresisting and anti-slipping material therein whichpermits a limited flowdeformation of the layer under a normal printingpressure.

Referring to the drawing, which illustrates one embodiment of thisinvention utilized in a textile printing machine: l 1

Fig. 1 is a vertical elevation, partly in section, of a preferred formof backing cylinder;

Fig. 2 is a fragmentary and somewhat dia-- grammatic front elevation ofa portion of the.

textile printing machine carrying this, backing The cylinder associatedwith one of a plurality of printing rolls; and

Fig. 3 is a fragmentary end view of the machine of Fig. 2.

A textile printing machine of standard construction comprises a largebacking cylinder in supported on a shaft or mandrel l l which has itsends mounted in suitable bearings [2 arranged for free rotation of thecylinder. The bearings may be adjustably mounted in any suitable manneron the two parallel spaced side frames M of the machine. The adjustmentmay be effected by means of the two screws l5 and i5 suitably threadedin the frame which movably engage the housings of the bearings f2. Theother member of the printing couple is a printing roll l8 which isusually made of an engraved copper sleeve removably fitted onto amandrel l9. The machine may be provided with a, plurality of theseprinting rolls. The ends of the mandrel l9 are suitably carried inbearing housings slidably mounted on the slide arms 2| which are formedas a part of the side frames 14. Pressure screws 22 threaded throughportions 23 of the frame carrying the slideways are arranged to move theends of the mandrel to force the printing roll it against the cylinderIll under high pressure. An inking roll 25 suitably mounted in an inkreceptacle 26 is driven by means of a pair of gears 21 suitably mountedon the printing roll and the shaft of the inking roll. The printingrolls are normally driven in synchronism by means of the large bull gear30 mounted on a short shaft 3| suitably mounted on one of the sideframes 14 and this gear engages the further gear 32 on the end of eachprinting roll mandrel. The fabric 33 to be printed is conducted over aguiding roller 34 into the printing zone defined by the printing rollsand the backing cylinder and it is drawn forward, either alone or with aback gray cloth and/or blanket, by the frictional force of thepositively driven printing rolls. Numerous other constructional featuresmay be employed, as is well understood in the industry.

In accordance with this invention, I have provided a backing cylinderwhich may be used with a plurality of printing rolls or which isarranged to receive the pressure of a single printing roll, such as isfound in a printing machine having a separate backing cylinder for eachof a plurality of printing rolls. As shown in Fig. 1, this backingcylinder may comprise a rigid supporting drum or roll 35 made of metalor other suitable material which carries a layer 35 of elastic materialon its peripheral surface. A preferred construction is one in which ahollow substantially cylindrical metal drum 35 is mounted on spacedspiders 31 which in turn have their hubs suitably secured on thesupporting shaft or mandrel II. The metal drum or roll 35 is shaped toprovide a slightly crowned convex or barrel shaped outer peripheralsurface 38. For example, an iron cylinder may be turned in a lathe toprovide a diameter of 29.931 inches at the central portion which tapersto a diameter of 29.875 inches ad acent its edges, thus providing acrown of 0.056 inch. The crown may be varied widely in accordance withdesired printing operations, and particularly depending upon the curveof the line of contact of the printing roll with the backing cylinderwhich is developed by the pressure that will normally be applied to thatprinting roll. The surface 38 may be shaped to fit geometrically thecontact line of the bent printing roll or any other desired curvaturemay be applied thereto. The printing roll bends only a slight amount andthe surface 38, as will be understood, need not fit or correspond withthat curvature, because of the resiliency or elasticity anddeformability of the elastic layer 36.

The outer layer 36 is made of a suitable elastic medium, and preferablya vulcanized rubber or a synthetic substitute therefor. This rubberlayer is preferably made as thin as is feasible for the requiredprinting operation since a thick rubber layer tends to bunch up inadvance of the printing roll. For example, this rubber layer may beapproximately inch thick. Various types of rubber or other elasticmedium may be employed within the knowledge of one skilled in the art,but I preferably use a vulcanized rubber which measures from 5 to 8 onthe plastometer scale. The rubber layer may also be provided withreinforcing strengthening material which resists the tendency for therubber to flow or which forms a roughened surface, such as may beprovided by incorporating therein fibrous material, such as cotton orwoolen fibres. These fibres are preferably short and small in size, andtheir main ber layer having cotton fibres therein is madev approximatelythick and has a plastometer reading of from 5 to 10. I, however, may usemuch harder rubber, such as ebonite, or other suitable-medium having aplastometer reading of 2 or as desired. A wide variation may be made inthe type of elastic material that is applied, to the backing cylinder aswill be understood. It may be also noted that the iron cylinder ispreferably given its crown shape by being turned on a lathe which leavescomparatively coarse marks thereon, which aid in holding the rubberlayer in place. This rubber may be vulcanized on the iron backingcylinder so as to make an integral union therewith.

The rubber layer is preferably provided with a substantially cylindricalsurface on its outer side. This insures proper contact with the fabricto be printed where the pressure is so light as not to deform theprinting roll or backing cylinder surface. That is, if the printing rollprovides a straight line contact, the rubber layer of the backingcylinder likewise provides a parallel straight line contact and the twomeetproperly throughout the entire width of the fabric. If on the otherhand, the printing roll is forced under an enormous pressure against thebacking cylinder sufficient to bend one of the parts, then that pressurewill deform the outer portions of' the rubber layer and provide a wideconcave band of contact between the fabric and the printing roll. Thisis particularly desirable where the engraving is fine and heavy pressureis needed to force the cloth into intimate contact with the recessedportions of the engraving. In that case, the rubber layer squeezes.under that pressure to contact fully with the printing roll. The rubberlayer may be shaped to provide a convex crowned surface, which maycorrespond with the crown on the iron drum and thus provide sub- By thisconstruction I compensate for any variations in the shape of theprinting roll or cylinder due to the bending of its mandrel and insurethat the pressure against the fabric is,

either equalized throughout its width or so controlled as to insure aproper printing contact. Also, the rubber layer has other desirableualities in that it leaves no printing marks on the fabric, such as issometimes caused by the overlapped end of the cloth wrapped on the roll.The rubber surface may be made smooth or it may be made rough byknurling or by the inclusion of asbestos, cloth or other fibrousmaterial or otherwise shaped as desired." Many other advantages will beapparent to one skilled in this art. 7

Since many modifications may be made in the construction as will now beappreciated by one skilled in the art, it is to be understood that theabove description is to be interpreted as illustrating the generalprinciples of my invention and the preferred embodiments thereof and notas imposing limitations on the scope of the claim appended. hereto.

I claim:

A backing cylinder associated with the printing roll in a textileprinting machine comprising a rigid support provided with a convexcrowned surface and an elastic deformable layer secured thereto whichhas a substantially cylindrical peripheral surface, said layercomprising a vulcanized rubber compound containing separate, short,reinforcing fibres incorporated therein, said rubber compound having aplastometer reading of from Etc 10 and an elasticity which permits itssurface to deform into a narrow concave band of contact between a fabricbeing printed and the printing roll under a normal pressure load, andthe fibres forming a rough anti-slipping surface and reinforcing therubber and limiting its flow while permitting deformation thereof.

JOHN HAROLD MAY.

